Surface treatments to impart hydrophilicity

Abstract

Water insoluble polymers are treated to place on their exposed surfaces the pendant alkyl imidocarbonyl (amide) groups to impart a high degree of hydrophilicity to that surface. Nitrile-containing polymers or copolymers in the form of insoluble films, filters or membranes are treated to convert a substantial fraction of the surface nitrile groups into the corresponding amide by the use of hydrogen peroxide or concentrated acids. The surface is rendered hydrophilic and resistant to fouling to the extent that even proteins are not denatured thereupon. The surface may also be converted to substituted amides by subsequent reactions to impart to it other functionalities or to serve as the basis for coupling reactions. Other polymers capable of surface treatment to produce pendant amidocarbonyl groups include ones containing pendant esters which on cleavage of the oxygen-carbon bond give pendant alcohol groups. These are converted by cyanoethylation to form the pendant nitrile groups which can be converted to the amide. Other polymers which on hydrolysis give pendant carboxylic acids can be treated with ammonia to also produce pendant amide groups.